8. Coderbyte [x]This offers some video tutorials and challenges for a few languages, plus special courses on specific algorithms and bootcamp/interview prep. You need a premium membership for quite a lot of things, though (e.g. I don’t think you can watch any of the videos with a free membership).

Languages: Python, Ruby, JavaScript

Extras: Algorithms, Bootcamp Prep, Job Interview Prep

9. Free Code Camp [x]Mini tutorials followed by mini challenges. Has a number of courses on the languages below!

Languages: HTML/CSS, jQuery, JavaScript

Extras: Git, Algorithms, + a bunch of projects to complete

10. Programmr [x]Has courses to learn various languages through doing little exercises/challenges in the browser, similar to previous examples. Also has ‘zones’ for more languages, where you can find challenges, example code and projects people have shared.

Languages: Python, Java, C++, C#, PHP, jQuery

11. CheckIO [x]Only offers Python, but I still think it’s really great. You move from level to level, getting challenges which are gradually trickier. Learn by doing!

12. Rails for Zombies [x]For people who already know a bit of Ruby, but nothing about Ruby on Rails! Each level begins with a short video followed by interactive challenges where you program Rails in the browser.